Why Diets Don’t Work: The Brilliant & Ruthless Way Our Body Self-Regulates

Set Point Theory 

Set point theory dictates that there is a specific genetically determined point around which our body weight fluctuates. You can more accurately think of it as a set range. It’s kinda like a thermostat. If the thermostat is set at 72º, your living room might fluctuate between 70º and 74º but on average, it’s gonna be at 72º. The same is true for our body fat. There’s a range we are genetically programmed to maintain, controlled by the hypothalamus in our brain. (2)

Body diversity is real

Some people are genetically programmed to maintain a lower percentage of body fat. Others are genetically programmed to maintain a higher percentage of body fat. It’s no different than height or chest hair. Some bodies are tall. Other bodies are short. Some bodies have a lot of chest hair. Other bodies have very little chest hair. I, for example, have an underwhelming amount of chest hair which I’m still very proud of, thanks for asking.

What happens when we drop below our set point?

The farther we get from our set point, the more intense our biological systems fight to return us to baseline.

If, for example, we diet down below our set point, our body gradually and systematically starts to rebel. It will produce more hunger hormones and less satiety hormones to encourage us to eat more. It’ll down regulate our body temperature to help preserve calories. It’ll also quietly convince us to voluntarily expend less energy measured by what we refer to at NEAT or Non-Exercise Activity Thermogenesis. (2)

As we get further from our set point, our body will methodically shut down systems that are less necessary for our immediate survival (like our libido for example.) It’s really beautiful in a tragic sort of way how brilliant and ruthless our body is at self-governing when calories are severely restricted. It’s also worth noting that the body doesn’t distinguish between voluntary food restriction and starvation. To the body, a diet is the same as a famine. (1)

What happens when we rise above our set point?

Honestly, not much. Like all of our physiological adaptations, there is good reason for this. For most of human history, food has been scarce. For millions of years, starving has been a greater biological threat than weight gain. While our system does everything it can to prevent us from dropping too far below our set point, we don’t have the same intense biological responses on the top end because we simply haven’t evolved to survive in an environment where food is bountiful. (1)

How is our set point affected by our modern world? 

Let’s keep it real…we live in a country of abundance. This is America after all, excess is basically a national sport. (Food scarcity is still a massive issue that deserves both national and global attention, but for many of us, we are fortunate to have enough to eat.) 

Ever since the industrial revolution, food has become more abundant, more shelf-stable, and from what I’ve been told, far more tasty. This is no accident. Processed food is painstakingly engineered for an optimal pleasure point, which is overriding our natural feedback mechanisms and undoubtedly encouraging us to eat more than we might otherwise. This modern food-stuff is cheap, easy to transport, convenient to store, and delicious. It can’t be any surprise we’re eating more of it. 

Add to this the fact that ever since the digital revolution, many of us simply don’t have to move as often. We sit in front of screens (small, medium, and large) that transport an entire universe of information to our finger tips often with a side order of buffalo wings. This lack of movement disconnects us even further from our body and prevents us from keeping our weight-regulatory systems balanced. (1) Physically speaking, we have to recognize just how unnatural this modern world is that we’ve created. I want to be very clear here. I’m not saying we’re thin or large based on our eating and movement habits alone – that is false. I’m saying that at the population level, our unnatural environment isn’t helping us maintain a natural set range.

And yet still, the story gets even more complex. Because we’re no longer eating from a place of physiological need, social and psychological factors are running the show (2). From an early age, we’re being advertised to about what and when to eat. We often turn to food not because we’re hungry but because we’re stressed, bored, distracted, or simply because it’s there and looks delicious. Food is big business and to the companies doing everything they can to increase consumption, our health isn’t nearly as important as their bottom line. 

Yo-yo dieting: the worst villain of all? 

Having become a country obsessed with both thinness and instant results, the $72 billion diet industry has created a perpetual cycle of extreme weight loss and subsequent (natural) weight gain. (4)

Here’s the irony. Extreme dieting has a tendency to move our set point up. As the story so often goes, if you diet down well below your set point, your body has a strong biological response which almost always wins. As additional insurance against another “famine” (or diet) your body will adjust your set point higher. This makes weight cycling one of the most effective methods for long term weight gain. (1)

So what should we do with all this information? 

Fighting our set point is a losing battle. The best we can hope to do is work towards remaining within our set range. But it’s not like there’s a test you can take that will reveal your biologically determined set point. The only way to determine your set point is to work towards eating to appetite on a regular basis. While this might sound simple, for many people, it’s anything but. 

Diet culture has created a massive disconnect between our body and our food. We’re constantly trying to manipulate calories, macros, and food timing to finagle our body into looking a certain way. The truth is, our body doesn’t care how we want it to look. It has far more pressing concerns, like keeping itself alive. By learning to respect and appreciate our bodies natural feedback mechanism, we can do a much better job of maintaining an easy and joyful relationship with food. 

Easy and joyful sounds nice. What are some actionables? 

1) We need a far greater appreciation for body diversity. Everyone isn’t designed to look like a cover model. Even as we work to create a healthier world, there will still be large bodies and small bodies, tall bodies, and short bodies, more chest hair, and less chest hair. This should not only be accepted, it should be celebrated as part of what makes humanity spectacular. 

2) We need to shift far more time, energy, and resources towards the social determinants of health. Personal choice matters and while it’s the easiest for us to control, it isn’t the only or even the most critical factor in health outcomes (3). If we want to improve the health of our country, we have to change food systems, food marketing, government subsidies, health care access, health care bias, physical education, and access to community resources. These are big problems that sometimes feel out of reach, but the solutions will have big affect. If we’re going to take these issues seriously, at the very least, we have to start talking about them.

3) We have to better understand the issues of diet culture and the lies we’re being told. It’s difficult work to parse apart what is legitimate information from what is downright bullshit. So as not to parse words, fast weight loss is a bad idea. Extreme nutrition plans are a bad idea. Dieting in general is a bad idea (for most people.) Successful weight management can only be a slow, gentle, and steady process. To suggest otherwise is a special kind of evil that sells false hope and fake science.

The relationship we have with our body is the most important of our life. Like all good relationships, it will require some give and take, some tough love and some coddling, and an enormous amount of communication. That’s why it’s tricky. Cultivating a good relationship with our own body is a lifelong process, but what better time to start than now? 

Curious to hear you thoughts. If you found this helpful, drop me a note on social media.

Works Cited

(1) Bacon, Lindo, and Aphramor, Lucy. Body Respect. BenBella Books, Inc. 2014.

(2) “Set points, settling points and some alternative models: theoretical options to understand how genes and environments combine to regulate body adiposity.” John R. Speakman, David A. Levitsky, David B. Allison, Molly S. Bray, John M. de Castro, Deborah J. Clegg, John C. Clapham, Abdul G. Dulloo, Laurence Gruer, Sally Haw, Johannes Hebebrand, Marion M. Hetherington, Susanne Higgs, Susan A. Jebb, Ruth J. F. Loos, Simon Luckman, Amy Luke, Vidya Mohammed-Ali, Stephen O’Rahilly, Mark Pereira, Louis Perusse, Tom N. Robinson, Barbara Rolls, Michael E. Symonds, Margriet S. Westerterp-Plantenga. Dis Model Mech. 2011 Nov; 4(6): 733–745. doi: 10.1242/dmm.008698 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3209643/

(3) “Social Determinants of Health.” Centers for Disease Control and Prevention. https://www.cdc.gov/socialdeterminants/index.htm

(4) “The U.S. Weight Loss & Diet Control Market” Research & Markets. https://www.researchandmarkets.com/research/qm2gts/the_72_billion?w=4

If you liked this blog post, you’ll love the sequel.